Arsenic An Invisible Poison in Drinking Water Taehyun Roh, PhD - - PowerPoint PPT Presentation

Arsenic

An Invisible Poison in Drinking Water

Taehyun Roh, PhD

Department of Epidemiology and Biostatistics School of Public Health Texas A&M University

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Arsenic

King of Poisons Poison of Kings No odor No color No taste

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Arsenic in Groundwater

Arsenic and Cancer

Lung Liver Kidney Bladder Skin

“There is sufficient evidence that inorganic arsenic causes cancers of the urinary bladder, lung and skin. Positive associations with cancer of kidney, liver, and prostate has been observed.” (IARC, 2004)

“Group1 Carcinogen”

Prostate

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City of Antofagasta in Chile

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Region II (Antofagasta), Chile

Driest habitable place

• n earth

Mars

• Development of mining industry ► Population growth

► Drinking water shortage ► Supplement with new water source (high arsenic level)

Arsenic in Drinking Water of Antofagasta

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Average arsenic level in 1958-1970

870 µg/L

Current regulatory level: 10 µg/L

New water source New water treatment plant

Unique Exposure Scenario

• Distinct high exposure period:

sudden major increase and drop (1958-1970)

• Limited water source:

whole population drank same municipal water in Antofagasta (> 125,000 people)

• Good exposure record
• Adequate latency

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• 1. Is arsenic in drinking water associated with an increased

cancer mortality up to the year 2010: 50 years after high exposures first began?

• 2. Is there an effect of age at first exposure on the association
• f arsenic in drinking water and bladder cancer mortality?

Questions

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Is arsenic in drinking water associated with an increased cancer mortality up to the year 2010: 40 years after high exposures stopped?

Question 1

Smith et al. (2018). Lung, bladder, and kidney cancer mortality 40 years after arsenic exposure reduction. Journal of the National Cancer Institute, 110(3), 241-249.

Arsenic and Cancer Mortality in Antofagasta (2001-2010)

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Standardized Mortality Ratio in Antofagasta, compared to the rest of Chile

Arsenic-related cancer mortality due to arsenic exposure can have very long latencies, with increased risks manifesting 50 years after first exposure.

High Exposure

Mortality up to year 2000

High Exposure

Latency of Arsenic-Related Cancers in Antofagasta

Age-adjusted rate ratios for cancer mortality for Region II (arsenic-exposed), compared with Region V (unexposed), Chile (1950–2010)

Lung Cancer Bladder Cancer

High Exposure

Kidney Cancer

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Question 2

Is there an effect of age at first exposure on the association

• f arsenic in drinking water and bladder cancer mortality?

Roh et al. (2018). Age at exposure to arsenic in water and mortality 30–40 years after exposure cessation. American journal of epidemiology, 187(11), 2297-2305.

Early-Life Exposure to Arsenic and Cancer Mortality

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Effect of Age at First Exposure to Arsenic on Cancer Mortality

SMR

Age at First Exposure

Bladder Cancer Laryngeal Cancer Lung Cancer Kidney Cancer

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Demographic, Lifestyle-Related, and Medical Risk Factors of Antofagasta and all of Chile

Demographic, Lifestyle-Related, and Medical Risk Factors of Antofagasta

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Smoking rate of Antofagasta and the rest of Chile

Bladder cancer-specific relative risk by smoking = 1.5 (Cumberbatch et al., 2016)

Demographic, Lifestyle-Related, and Medical Risk Factors of Antofagasta

Conclusion

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• Arsenic-related cancer mortality is still very high

even 40 years after the high exposure stopped

• Major impacts on people who probably experienced

early life exposure

Acknowledgement

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Arsenic Health Effects Research Program

• Craig Steinmaus, MD, MPH (director)
• Allan Smith, MD, PhD
• Meera Smith, PhD
• Jane Liaw, MPH

Collaborators

• Pontificia Universidad Católica de Chile
• Catterina Ferreccio, MD, MPH
• Guillermo Marshall, PhD

Thank you!

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